This invention relates to coffee concentrates, and in particular, to a liquid coffee concentrate that is processed and packaged under aseptic conditions to produce a high-quality and shelf-stable concentrate derived from a cold temperature extraction process.
The brewing of coffee using only coffee beans and water is an art practiced through the world. While many different coffee beans, roasting and grinding techniques, bean/water ratios may be used based on regional and cultural preferences, the basic hot extraction method remains similar. Therein, the bean in desired form is exposed at an elevated temperature for a period of time sufficient to extract the desired constituents for the taste of the end consumer. Against such background, it is widely accepted that excessive brewing temperature can adversely affect the palatability of the resulting brew. Similarly, insufficient brewing temperature results in insufficient extraction and an undesirably weak brew. Further, it is widely accepted that reheating a properly brewed coffee to excessive temperatures can also adversely affect the desired taste. Accordingly, notwithstanding advances in automatic equipment available to the consumer, brewing a highly palatable coffee remains an elusive challenge.
Recently, in addition to regularly brewed coffee, specialized coffee drinks have become popular. Mocha, espresso, cafe latte, cappuccino and the like require brewing techniques not readily and reliably practiced in the consumer setting, and accordingly are available primarily only at commercial settings having specialized equipment and personnel for such products. Also, cold coffees are becoming popular and require a non-bitter coffee concentrate that will maintain desired flavor in the presence of dilution with ice and additives.
In an effort to provide the consumer and the commercial establishment with a wide variety of hot and cold coffee based beverages that can be reliably and repetitively served without specialized equipment, an effort has been made to provide coffee concentrates that can be heated, diluted, cooled, processed and formulated for such applications. However, the basic constituents of coffee have prevented acceptably shelf-stable products from being successfully developed. Coffees, unlike many food and beverage concentrates, deteriorate in unacceptable ways due to enzymatic and bacterial degradation. While such reactions can be retarded through refrigeration, such storage is expensive and effective for limited time periods and compromised unless completely utilized at first consumption, inasmuch as the temperature transients in handling outside the refrigerated setting can accelerate and resume the undesired reactions. Such limitations also reduce the availability and increase the cost of such products to the consumer inasmuch as refrigerated shelf space is expensive in storage or retail facilities. Further, conventional processing and packing techniques have not provided a satisfactory solution. Coffee is an exceedingly complex liquid of aromatics, oils and other flavor and texture enhancing entities contributing to the recognized taste criteria of acidity, body, aroma, flavor and essence. These qualities by presence or absence determine quality and acceptability of the brewed coffee to the consumer.
As to processing, proper extraction is required under controlled time and temperature conditions. Excessive brewing temperature results in excess acidity and off-taste characteristics and, accordingly, experienced brewers and packagers go to great lengths to avoid excessive temperatures. As to packaging, the efforts to provide refrigerated or non-refrigerated shelf life to coffee and coffee concentrates while retaining the desirable taste criteria are in processing conflict. Thermal processing for reducing bacterial and microbial constituents when successful does so at the expense of flavor loss. Undesirable changes in the qualities resulting from reaction between the coffee constituents. Merely providing elevated high processing temperatures has not produced satisfactory product.
One such prior art approach as disclosed in U.S. Pat. No. 228,889 to Gue et al. wherein separate cold and hot extracts are obtained for appropriate dilution at time of use. Therein, it is recognized air exposure is detrimental. Additives are incorporated to avoid the loss of desirable coffee qualities.
U.S. Pat. No. 4,983,408 to Colton discloses obtaining an extract by contacting an aqueous mixture of coffee with pressurized steam followed by enzyme treatment to produce a concentrate that may be reconstituted or converted to a soluble solid. No ambient temperature shelf life it attributed to the resultant product.
U.S. Pat. No. 1,393,045 to Scott discloses a heat exchange evaporation to produce a coffee concentrate without any process provisions for attaining ambient shelf life.
U.S. Pat. No. 3,860,940 to Sivetz discloses a process of hot water injection into a column containing coffee thereby producing a concentrated coffee vapor phase that is liquefied and packaged. No process provisions are incorporated for eliminating enzyme or bacterial degradation in the concentrate.
U.S. Pat. No. 2,497,721 to Foulkes discloses a high temperature extraction to which sodium phosphate and propylene glycol are added as stabilizers. Flash pasteurization or post packaging high temperature sterilization are employed to increase shelf life. The suggested temperature and processing conditions are not currently regarded as appropriate.
U.S. Pat. No. 4,618,500 to Forquer discloses a method for producing espresso-type coffee using low temperature and pressure brewing to form a concentrate followed by low temperature cooling for producing a product suitable for storage under refrigerated conditions.
U.S. Pat. No. 5,637,343 to Ryan discloses an ambient temperature extraction for forming a concentrated followed by microfiltration for removing bacteria from the process water and concentrate for enabling non-refrigerated storage. No post extraction procedures are employed for removing non-filterable pathogenic material.
From the foregoing, it will be apparent that the prior art has sought through many routes to provide a stable concentrate, but in the process has introduced excessive temperatures for extraction or thermal treatment now known to be incompatible with consumer preferred tastes, required chemical additives not favored by consumers, only partially removed pathogenic material contributing to taste degradation, or required expensive refrigerated storage prior to sale or use.
Thusly, a well established need continues to exist for a packaged coffee product, in concentrated or dilute form, having extended storage life at ambient temperatures that retains full flavor without diminution over time and may be formulated with ordinary equipment and techniques into a wide menu of popular coffee formats.
Accordingly, it is an object of the present invention to provide an extended shelf life coffee product retaining the flavor characteristics of freshly brewed product.
Another object of the invention is to provide a process for packaging coffee concentrate for long term storage under non-refrigerated conditions without a loss of desirable taste characteristics.
A further object of the invention is to provide an aseptically packaged coffee having extended ambient temperature storage without the use of chemical additives.
Yet another object of the invention is to provide a packaged liquid coffee that is shelf-stable for extended periods at ambient temperatures and does not contain undesirable flavoring when processed for consumption.
The foregoing objects and features are provided in accordance with the present invention by a coffee concentrate extracted, processed and packaged under time, temperature and pressure conditions effective for reducing microbial content sufficient for long term ambient storage and producing a coffee product having all desirable flavor characteristics of freshly brewed coffee consumables. More particularly, coffee beans and non-processed water, only, are admixed under ambient conditions for a period of time to achieve a desired extraction of the desired coffee constituents, either in concentrated or diluted form. The coffee extraction is then processed at elevated temperature and for a time and under pressure sufficient to reduce microbial content to a level by which the content may be aseptically packaged to produce a product that can be stored for extended periods without refrigeration, and when consumed either in coffee drinks directly based on the concentrate strength or diluted appropriately for regular coffee products produces acidity, body, aroma, flavor and essence associated by coffee consumers with a freshly brewed product. The previously experienced untoward results of elevated temperatures, required for acceptable microbial reduction, have been found to be tolerated by processing the concentrate at time and temperature conditions having an F0 value in the range of 1.0 to 12.0 under moderate pressure conditions. After such processing the thermally treated concentrate is rapidly cooled and processed under conventional aseptic packaging techniques. When consumed, at concentrate strength or diluted strength, after ambient storage, the desired characteristics are retained.